scholarly journals Quantification of Tau in Cerebrospinal Fluid by Immunoaffinity Enrichment and Tandem Mass Spectrometry

2014 ◽  
Vol 60 (4) ◽  
pp. 683-689 ◽  
Author(s):  
Thomas McAvoy ◽  
Michael E Lassman ◽  
Daniel S Spellman ◽  
Zhenlian Ke ◽  
Bonnie J Howell ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cerebrospinal Fluid ◽  
Tandem Mass Spectrometry ◽  
Magnetic Beads ◽  
Internal Standard ◽  
Tandem Mass ◽  
Limit Of Quantification ◽  
Total Tau ◽  
Liquid Chromatography Tandem Mass ◽  
Full Scan

Abstract BACKGROUND Cerebrospinal fluid (CSF) tau is a common biomarker for Alzheimer disease (AD). Measurements of tau have historically been performed using immunoassays. Given the molecular diversity of tau in CSF, the selectivity of these immunoassays has often been questioned. Therefore, we aimed to develop an analytically sensitive and selective immunoaffinity liquid chromatography–tandem mass spectrometry (LC-MS/MS) (IA-MS) assay. METHODS IA-MS sample analysis involved the addition of an internal standard, immunoaffinity purification of tau using a tau monoclonal antibody coupled to magnetic beads, trypsin digestion, and quantification of a surrogate tau peptide by LC-MS/MS using a Waters Trizaic nanoTile ultraperformance LC microfluidic device. Further characterization of tau peptides was performed by full-scan MS using a Thermo Orbitrap LC-MS. CSF samples from a cohort of age-matched controls and patients with AD were analyzed by the IA-MS method as well as a commercially available immunoassay. RESULTS The IA-MS assay had intra- and interassay imprecision values of 3.2% to 8.1% CV and 7.8% to 18.9% C, respectively, a mean recovery of 106%, and a limit of quantification of 0.25 pmol/L and was able to quantify tau concentrations in all human specimens tested. The IA-MS assay showed a correlation of R2 = 0.950 against a total-tau immunoassay. In patients with AD, tau was increased approximately 2-fold. CONCLUSIONS Combining immunoaffinity enrichment with microflow LC-MS/MS analysis is an effective approach for the development of a highly selective assay to measure total tau and, potentially, other posttranslationally modified forms of tau in CSF.

scholarly journals Determination of esomeprazole in rabbit plasma by liquid chromatography tandem mass spectrometry (LC-MS/MS)

2021 ◽  
Vol 4 (1) ◽  
pp. 6-10
Author(s):  
Anh Le Minh ◽  
Tung Nguyen Thach ◽  
Nam Nguyen Nhu ◽  
Dong Bui Quang ◽  
Dat Pham Thanh ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Internal Standard ◽  
Tandem Mass ◽  
Rabbit Plasma ◽  
Bioanalytical Method Validation ◽  
Limit Of Quantification ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

A rapid extraction method was developed and validated for esomeprazole determination in rabbit plasma by liquid chromatography tandem mass spectrometry (LC–MS/MS). Esomeprazole in rabbit plasma was extracted and then cleaned up using QuEChERS technique. The analyte was separated using C18 column and quantified by MS/MS detector. Pantoprazole was used as the internal standard. The positive ESI source was used in this study together with the multi­-reactive ion monitoring mode. The validity of the method has been confirmed in accordance with ICH Harmonized guidelines on bioanalytical method validation. The method showed good specificity, good stability, with the linearity varying from 0.1 ng/mL to 20 ng/mL, the lower limit of quantification was 0.1 ng/mL, the accuracy and precision were within 85% and 115% which achieved the ICH Harmonized guideline requirements, FDA guideline and AOAC International requirements. The method has been applied to quantify the concentration of esomeprazole in rabbit plasma, and then to compare the bioavailability of two preparations containing esomeprazole.

scholarly journals Development of a method for the measurement of dehydroepiandrosterone sulphate by liquid chromatography-tandem mass spectrometry

2005 ◽  
Vol 42 (6) ◽  
pp. 468-474 ◽  
Author(s):  
C A Chadwick ◽  
L J Owen ◽  
B G Keevil
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Lower Limit ◽  
Internal Standard ◽  
Tandem Mass ◽  
Dehydroepiandrosterone Sulphate ◽  
Chromatography Tandem Mass Spectrometry ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass

Background: Dehydroepiandrosterone sulphate (DHEAS) is a steroid that is increasingly being recognized as a potential drug of abuse in many countries. This is due to its reputation as a hormone that may be able to retard the ageing process. The measurement of DHEAS is useful in the diagnosis of medical conditions such as congenital adrenal hyperplasia and polycystic ovary syndrome. Thus, a liquid chromatography-tandem mass spectrometry method has been developed to determine DHEAS concentrations in human serum. Method: The chromatography was performed using a WatersTM 2795 Alliance HT LC system coupled to a Mercury Fusion-RP column fitted with a SecurityGuardTM column. Results: DHEAS and the internal standard, deuterated DHEAS, both had a retention time of 1.5 min. The transition determined by the Micromass QuattroTM tandem mass spectrometer for DHEAS was m/z 367.3>96.7 and for the internal standard m/z 369.3>96.6. The method was linear up to 20 µmol/L; the lower limit of detection and the lower limit of quantitation were both 1 µmol/L. The intra- and interassay imprecision were <11% over a concentration range of 1-18 µmol/L for the in-house quality control and <12% for the intra- and interassay imprecision for the Bio-Rad Lyphocheck QC. Conclusion: The measurement of DHEAS by liquid chromatography-tandem mass spectrometry is robust and has a simple sample preparation procedure with a rapid cycle time of only 4 min.

scholarly journals Liquid Chromatography-Tandem Mass Spectrometry of Desoxo-Narchinol a and Its Pharmacokinetics and Oral Bioavailability in Rats and Mice

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2037 ◽  
Author(s):  
Subindra Kazi Thapa ◽  
Mahesh Upadhyay ◽  
Tae Hwan Kim ◽  
Soyoung Shin ◽  
Sung-Joo Park ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Oral Bioavailability ◽  
Internal Standard ◽  
Rat Plasma ◽  
Tandem Mass ◽  
Mouse Plasma ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

Desoxo-narchinol A is one of the major active constituents from Nardostachys jatamansi, which has been reported to possess various pharmacological activities, including anti-inflammatory, antioxidant, and anticonvulsant activity. A simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of desoxo-narchinol A in two different biological matrices, i.e., rat plasma and mouse plasma, using sildenafil as an internal standard (IS). The method involved simple protein precipitation with acetonitrile and the analyte was separated by gradient elution using 100% acetonitrile and 0.1% formic acid in water as a mobile phase. The MS detection was performed with a turbo electrospray in positive ion mode. The lower limit of quantification was 10 ng/mL in both rat and mouse plasma. Intra- and inter-day accuracies were in the ranges of 97.23–104.54% in the rat plasma and 95.90–110.11% in the mouse plasma. The precisions were within 8.65% and 6.46% in the rat and mouse plasma, respectively. The method was applied to examine the pharmacokinetics of desoxo-narchinol A, and the oral bioavailability of desoxo-narchinol A was 18.1% in rats and 28.4% in mice. The present results may be useful for further preclinical and clinical studies of desoxo-narchinol A.

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